1. Field of the Invention
The present invention relates, in general, to a novel genus of bacteria known as Ketogulonigenium. The present invention further relates to transformed Ketogulonigenium, and methods of transforming Ketogulonigenium. The present invention also relates to nucleic acid molecules, and vectors.
2. Background Art
The exploitation of microorganisms to synthesize vitamin C or its chemical pathway intermediates has both economic and ecological advantages.
One key intermediate in vitamin C synthesis is 2-keto-L-gulonic acid (2-KLG), which is easily converted chemically to L-ascorbic acid (vitamin C) by esterification followed by lactonization (Delic, V. et al., “Microbial reactions for the synthesis of vitamin C (L-ascorbic acid,” in Biotechnology of Vitamins, Pigments and Growth Factors, Vandamme, E. J., ed., Elsevier Applied Science (London & New York) pp. 299–336 (1989)). Members of a number of bacterial genera have been identified that produce 2-KLG from the oxidation of L-sorbose or sorbitol. Such 2-KLG producing genera include the acidogenic, alpha-proteobacteria Gluconobacter and Acetobacter, the gamma-proteobacteria Pseudomonas, Escherichia, Klebsiella, Serratia and Xanthmonas and the Gram positive Bacillus, Micrococcus and Pseudogluconobacter (Imai, K. et al., U.S. Pat. No. 4,933,289 (1990), Sugisawa, H. et al., “Microbial production of 2-keto-L-gulonic acid from L-sorbose and D-sorbitol by Gluconobacter melanogenus,” Agric. Biol. Chem. 54:1201–1209 (1990), Yin, G. et al., U.S. Pat. No. 4,935,359 (1990), Shirafuji, et al., U.S. Pat. No. 4,876,195 (1989) and Nogami, I. et al., U.S. Pat. No. 5,474,924 (1995)).
To aid in increasing the yield of bacterial products, attempts have been made to exploit endogenous plasmids within microorganism strains. (Beppu, T. et al., U.S. Pat. No. 5,580,782 (1996), Fujiwara, A. et al., U.S. Pat. No. 5,399,496 (1995); Tonouchi et al, U.S. Pat. No. 6,127,174 (2000), Hoshino, T. et al., U.S. Pat. No. 6,127,156 (2000)).